I need a little help myself. I found this in a creek near an old gristmill site. On one side of the creek there was a gristmill and on the other side was a sawmill. I've heard there was civil war activity in this area as well. Its fairly heavy and has a metal notch made to the inside.
At least I think the notch is made onto it... could be a rock fused to it because there are several small pebbles fused to it. Didn't want to start wacking on it with a pick and hammer ha.
I agree about the clock winding key but your piece looks like it could have been a collar to hold some sort of tool head on a wooden shaft? Just my guess.
Be sure to scroll through the image thumbnails below the first featured one. Many of the examples shown have articulated handles similar to yours. Until the early 20th Century most pocket watches still required a key to wind or set, not having the central crown winder such as is practically ubiquitous today. Other clocks in common use also required such keys to wind.
Ice and roller skates also required similar "skate keys" like wrenches to tighten them onto shoes or boots, typically with an incuse square at its end to wrench a matching screw fitting that operated clamps on the skate. However "skate keys" tended to be a bit larger than an inch, more like 2 or 3, and typically had simpler unarticulated handles.